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Picture of Solar Hot Air Balloon Message-in-a-Bottle
This is a hot air balloon made from trash bags and heated by the sun. Once airborne, it should stay up 'til the sun goes down or behind the clouds. Needless to say, it can travel a long, long way. Attached to it is a "message-in-a-bottle" asking anyone who might find it to email their location, just to see how far it flew. There's just something romantic about a message seeking out who-knows-whom in far away who-knows-where.


As a note, as boys, my brother and I lived on a tidal river in Florida. Walking the mangroves, we found a couple of messages-in-bottles that people sent. One came from another state. It said something like, "Send a postcard with your address and we'll send a present." My brother sent a note and sure enough they sent back a King James Bible (it was a "Fishing for Men" outreach project by a Georgia church). He still has that Bible. It was inspiring to think of how far that message had come and the path that it took. The magic of a message-in-a-bottle is to imagine, "Where will it go?" and, "Who will find this?"
 
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Step 1: Materials and Tools

Picture of Materials and Tools
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Materials

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1. Trash bags -- They must be THIN, I used 0.6 mil but the thinner the better. Most quality bags are heavy, at least 1.0 mil. We want the cheap-O bags.
2. Tape -- I used regular masking tape. Likely scotch tape is okay too. Don't use the wide package tape though--too heavy.
3. Thread
4. Pen and paper
5. Plastic bottle -- I actually had to get rid of the bottle because it added too much weight.

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Tools
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1. Scissors
2. Blow drier
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mentalman4 years ago
THis is TOO FUNNY a big argument over the moisture content of the air in tha bag BUT WAIT ! There's MORE .That bag can get caught in the JET ENGIONE of a plane. when that happens the plane will come down or land and They will read your message and know where you live. We used to set off huge bags with helium in them . and Like fools the bags had the company Logo on the side.
They were 10 feet long and we would watch them at the "Lunch Launch. But one day The cops showed up because they were getting in to the flight path of the Air port 15 miles away. We got 1 warning to stop. Next they would have put us in jail YEP that's fact.
you're a real d-bag, you know that?
plus, if it gets in a jet ENGINE, in would likely be destroyed. might not even hurt the ENGINE.
shomas KJ4ZVQ21 days ago

Plastic bag versus super heated pressurized air plus jet fuel inside a jet engine with titanium blades?????? Lets say shredded and burnt only to become fuel for the engine and adding to the its thrust.

shomas21 days ago

The volume of 1 mole of any gas at slandered temperature and pressure is 22.4 liters.


1 mole of oxygen gas (O2) = 32 grams. 1 mole of nitrogen gas (N2) = 28 grams. 1 mole of water (H2O) = 18 grams.

In terms of density (O2) = 32G/22.4L; (N2) = 28G/L; and (H2)=18G/22.4L

Water vapor, at 18 grams a liter has a lower density than the two main components of our atmosphere. liquid water is is not governed by gas laws and has a density of 18 grams per milliliter over a wide range of temperature. You don't need to separate the compounds in water to determine its density, but you do need the atomic masses of the atoms that make up water to determine molar weight.

rimar20004 years ago
Wonderful!

Damp air is lighter than dry air. Maybe you can inflate the balloon with your lungs (many persons, because it is a great volume) instead of the hair drier. That should give it longer scope/range.
Maybe you can get a spray bottle and 'spritz' the air going into your hair dryer. That possibly could make the air damp, especially if you put the heat on high.
DON"T DO THIS!!!!
The water will make the thing too heavy to fly, and you'll be too dead to observe the effect.

The volume of 1 mole of any gas at slandered temperature and pressure is 22.4 liters.

1 mole of oxygen gas (O2) = 32 grams. 1 mole of nitrogen gas (N2) = 28 grams. 1 mole of water (H2O) = 18 grams.

In terms of density (O2) = 32G/22.4L; (N2) = 28G/L; and (H2)=18G/22.4L

The bigger issue is with air a few degrees above ambient temperature, how do you keep water in vapor form rather than in condensed form. The answer is that it can hold only as much water as 100% humidity for a given temperature and pressure. at 100% humidity, a drop in temperature will cause water to condense to smaller than 1/1,600 its vapor form.

What people do not realize is that humid air or steam are tiny water droplets, it is not a separation of its compound of hydrogen and oxygen.
The dryer the air the lighter it will be. The less you compress air the lighter it will be also.
mossimo3 shortw4 years ago
Humid air is actually less dense then dry air. At ground level (anything in the troposphere) you have diatomic gasses, O² and N². O² has an atomic mass of 32, while N² has an atomic mass of 28; however, water has an atomic mass of 18, much less than that of the Oxygen and Nitrogen. As a result, by adding humidity to the air will displace the O² and N² thus making it less dense than a similar volume of air (without the added humidity). Density is m/V (mass/volume), and if you have "less" mass by displacing O² and N² molecules and replacing them with much lighter water molecules you will subsequently decrease the air's density.
Mossi, Rimar, you're missing the point! The water will quickly condense (i.e. become liquid ) on the plastic bag,because it is cooled by the outside atmosphere. Thus, it is not a gas, but a rather heavy load for the balloon to lift. Don't believe me? Try it!
I didn't tried it, but I think that if there is enough sunlight, the condensation does not occur.
You are wrong. The reason of all atmospheric phenomena is that the humid air is lighter than dry air.
Incredibly DANGEROUS and stupid idea...
Your post should be removed
Spraying water into a hair dryer? surely you jest!
as long as you don't spray salt water you should be fine. Saltwater conducts electricity more than tap water. Everybody knows that.
If you want to go the water route or humid air route, why not just put some H2O in the bag and let it evaporate inside the closed bag.
Distilled water would be the safest. Tap water has all kind of minerals and iron in it. Ever see rusty water? That's iron and it is conductive.
Too Funny!!!....... true salt water does conduct better than tap water..... Tap water will still kill you ... maybe you will not be as dead with tap water as with salt water but dead is still dead :-)
HERE's your sign!!!
just wondering how you came to the conclusion that damp air is lighter than dry air? 0_o
Air is about 78% Nitrogen (N2) , about 21% Oxygen (O2) and about 1% other gases. Nitrogen has a molecular weight of 14 so a N2 molecule has a molecular weight of 28. Oxygen has a molecular weight of 16 so an O2 molecule has a molecular weight of 32. given the ratios of air and the molecular weights of the components, air has a molecular weight of 28.6 (0.78 * 28 + 0.21 * 32 = 28.6).


Water is made up of two hydrogen and one oxygen atoms (H2O). Hydrogen is the lightest element and has a molecular weight of one. So a water molecule has a molecular weight of 18 (2 * 1 + 1 * 16 = 18). Water is a very light molecule and much lighter than the average weight of the molecules found in air.

as you can see above water vapor is lighter than air, and when the air is moist, water vapor displaces an amount of air (replacing heavier air with lighter water vapor), thereby making the moist air lighter. Of course the temperature and pressures must be the same for this to be true.


Included is a link to calculate weight of dry air, moist air and amount of water vapor in moist air.


https://www.brisbanehotairballooning.com.au/faqs/education/116-calculate-air-density.html


shortw deitzgen4 years ago
You calculated 2 different gases( hydrogen and oxygen), not water.
Now put the hydrogen and oxygen into a bond and use the right formulation to calculate the weight of water,
shomas shortw21 days ago

The volume of 1 mole of any gas at slandered temperature and pressure is 22.4 liters.

1 mole of oxygen gas (O2) = 32 grams. 1 mole of nitrogen gas (N2) = 28 grams. 1 mole of water (H2O) = 18 grams.

In terms of density (O2) = 32G/22.4L; (N2) = 28G/L; and (H2)=18G/22.4L

The bigger issue is with air a few degrees above ambient temperature, how do you keep water in vapor form rather than in condensed form. The answer is that it can hold only as much water as 100% humidity for a given temperature and pressure.

Yes, water vapor is a little lighter than air, but when it condenses on the bag, which is cooler than the air inside, it turns to liquid water, which is hundreds of times heavier.
Yes, liquid water is indeed heavier than water vapor by volume, but you don't just add mass. You keep the same mass you had, but it's in a smaller package.

Here, you have X grams of water in the form of vapor inside the bag (if you do the trick he suggested). Once the surface of the bag cools below the dewpoint for that humidity, those same X grams will drop out of vapor form into liquid water on the inside of the bag. But you won't ADD mass - it will just be in a different form.

By turning the vapor into liquid the bag's volume will decrease (since X grams of liquid water is a lot smaller than X grams of water vapor - remember the capped steaming tin can demo in high school). Thus the total mass of the airship will still be there but the volume will have dropped, making it more dense (density being mass/volume), so it will lose bouyancy.
Well, yes, Paymeister, I should have said 'hundreds of times heavier than the same volume of air', which is what I meant.
Yes, that is possible, but if the balloon is at full sun, is not as easy.
Should have incorporated this into my post above: to get to the dewpoint you'll need to cool it a fair amount, which won't happen in full sun.
It is not my conclusion, it is a fact. I am guiltless!
broccali1 year ago
maby if you get it to carry a heavier load you cen hook
up a solar panel to a
motor with a propeller
gwarbeh2 years ago
Awesome idea! I have to try this some day. I wonder how big you could make it, and whether making it much bigger would enable it to carry a heavier load.
10 foot weather baloons carr very littlt weight.
The idea might be good, but I hate the fact that this plastic probably will end up in the ocean where it can be deadly for mammals or other sea creatures. Or it may end up somewhere in the nature which is also a bad idea.
right
foobear2 years ago
Sooo... did anyone ever find it?
Innocent until proven guilty? sigh...
they can do what ever they want. if you are poor or dont have connections in the government and the state takes you to court and knows they will lose if they dont lie they will lie and are allowed to because they arent "under oath" see how that work? and your attorney will side with the state prosecutor to protect the state government. its something called the state claiming sovereign immunity and it works great with the state bar code of ethics to make the government employee pulling some scam right even when they arent. have you ever wondered why it is that government people when they harm a non government person gets off the hook on a technicality when it is clear they are guilty? the exception to this rule is if they government person is televised red handed in the act. true story even if its just video taped and not televised the government people will get off the hook oops i just made myself a target for pointing out the obvious
calebgeb2 years ago
wwwwwwwwwwwwwoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooowwwwwwwwwwwwwwwwwwwwww!!!!!!!!!!!!!!!!!!!!!!!!
Velin93 years ago
i made one but the wind blew it into a thorny bush: (.
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